Set-back concrete-form tie with re-usable anchor pieces



Feb. 3, 1959 E.KBEIRGDAL SET-BACK CONCRETE-FORM TIE WI'III RE-USABLEANCHOR P IECES Filed July 12, 1954 United States Patent SET-BACKCONCRETE-FORM TIE WITH RE-USABLE ANCHOR PIECES Ed Bergdal, Ellensburg,Wash.

Application July 12,1954, Serial No. 442,681

6 Claims. ('Cl; 2,5-131) The'invention pertains to concrete-form ties ofthe type in'which a primary tie member completely embedded in theconcrete is joined an inch or so within the face of the concrete tore-usable end members7 leaving the tie material within the concrete setback a predetermined desired distance from the face of the concrete whenthe end members, or anchors, are removed. The recesses left in theconcrete upon the withdrawal of the anchors may be filled with cementmortar, thereby achieving a smooth nish, and one which is free from ruststains produced by tie-ends at the surface, thus conforming tospecifications for exposed concrete surfaces requiring a blemish-freeiinish.

ItA appears that the at-all practical ties of this nature heretoforeused are those in which a screw connection of one type Ior another isused to join the separate members; these are expensive to manufacture,time-consuming to use, and tend to leave excessively deep recesses.these-reasons ties of this type are not generally used where they can bedispensed with. Ties of'simpler construction are commonly used whereIthe circumstances permit, to avoid the above disadvantages. These aregenerally ties each of'which extends, as a single member, throughtheforms on both sides of the Wall, and after the forms have been removed,the tie is twisted of'at or within the surface of the concrete at ayweak point in the tie provided for that purpose. Such ties, however,involve other disadvantages: on. an average, more than two-thirds of thetie material must be broken offand discarded after being used once, anexpensive procedure; to lcompensate for the weak placesneeded in suchfatie, the whole tie must be relatively heavy for its intendedstrength;the projecting endsof the-tie are a handicap duringthe construction andremoval of the forms; and the work of removing the projecting endsinvolves additional labor.

TheA present tie avoids both of the above two groups of; handicaps: itisvery` quicklyy applied, probably the mosti quicklyy applied of allset-back ties; it employsl a minimum amount of non-re-usable material,and the non-re-usable members are of very inexpensive manufacture; there-usablemembers are also quite simple, and w-ill compare favorably incost with other re-usable recess-forming anchor members forconcrete-form ties; andisince the overlap of` the parts at the jointswithin the concreteis'relatively slightg, the recesses need beonlyrelatively; shallowfor any given requiredV set-backv of theendszofftheembedd'ed part fromy the` face of the. concrete.

Fory

note-worthy featureof: present; invention is that when ythesettiesareused, the forms andthe projecting portions 4the anchory members of;the presentY tie is made possible through these fourf novel featuresembodied in this tie: Hirst, an anchor; which isL disengaged from thepermai neatly/embedded member, orrlink, by a rotaryl movement, istretable, on aniedge or corner-r of the. concrete afterthe rwice latterhas partly or completely set, thus dispensing with any need for a pivot,shaft, bolt, or pin about which to rotate the anchor, and for a mountingfor any rotationcentering means.` With a structure likethat used in thisdevice, this leaves the anchor removable even when the form is in place,which appears to be unique among rotatable anchors other than boltvanchors.

Second, the embedded portion of the anchor has substantially the form ofa quadrantal sectori of a` circle, which enables one to withdraw theanchor from the concrete with a direct outwardv movement after it, hasbeen rotated merely enough to disengage it' from thelink, incontradistinction to rotatable anchors used in other ties where anengagement prong has to be drawn by a rotary movement through arelatively long passage in they concrete.

Third, an arrangement wherebyy the anchor may be released from itsengagement with the back of the form through the movement of an off-setouter end portion of the anchor when the latter is rotated, as willy befurther explained.

Fourth, a simple and effective-locking device for maintaining theconnection between they link and the anchor while the tie is in activeoperation, which willr also be further explained.

ln brief, the invention consists of av non-re-usable link or equivalentstructure made from a light rod, aheavy wire, or other material, whichlink hooks onto aprojection on a re-usable anchor member at. either end,the connections being within theconcrete; the anchor members engage theback of the frame of the forms and are so constructed that they may berotated to a-limited-extent, such rotation yeffecting a disengagement ofthe anchors from the link; A lockingy pin, which may be a nail, preventssuch disengagement while the pin is in place. The anchors are preferablymade of malleable iron.

The views of theaccompanying drawing may be briey described as follows:

Figure 1 is a top view of'theprimary member or link shown separately.

Figure 2 is a side view. of the same.

Figure` 3 is a top View: of oneof the anchormembers in place in a form,with a portionof a connected link shown.

Figure 4 is a side, view corresponding toFigure 3.

The primary member'or' link may be made fromlight rodmaterial or heavy`Wire in a shapee resembling an elongated chain link, as indicatedin1Fi`guresz1 and' 2. The link is indicated in;A the, various viewsy bythe reference numeral 1. The ends of thezmaterial forming the link maybe lapped andithen electrically welded; Otherf'orms for the link arepossible, however; thus, one might use a single stem witha loop ateither: end, orv a at bar with holes punchedirrthe ends.

The two anchors inv ai tiel are of identical shape. An anchor is inFigures 3: and 4 designated by tlre'reference numeral 2. As seen inFigures 3v and 4, the anchor Z has -a portion 3l` embedded: intheconcreteC.V This portion has a formwhich, as; viewed from the side,is. substantially, though preferably not, absolutely, that of" aquadrantal sector of ia; circle. The. arc ofi thisf figure, which gureit is convenient to designate as a sector, is preferably notain-absolutely,4v true circular curve, but an involute spiral, or. somesimilar curve, so that'v a4 slight amount ofrotationV of theV sectorabout its' vertex will eliminate the peripheral friction' whichotherwise would be a hindrance throughout` all ofV the rotationnecessary to free the anchor from its engagementv with the link. As maybe seen in- Figure 3, the portion 3 tapersfrom a, point opposite thesurface of` the concreteto the: inner endwhere it connectswithrthe'linkg: with such'` a taper .of the holes 4.4, indicated bybroken lines.

-after the concrete is set.

.tremity of portion 3, the general direction of this projection beingparallel vwith the arc of the sector.

Through the upper part 3.2 of the portion 3, lying outside of the fnotch3.3, is a hole 3.4, indicated by broken lines.

`The portion 4 of the anchor 2 extends from the surface of the concrete,that is, from the face of the form sheathing, to the outside or backsideof the form. At a right angle across the outer end of the k.anchor is abar 4.1 which engages the stud St. Bar 4.1 extends laterally in bothdirections, so that the anchor may readi- .ly beused on either side of astud. The anchor is held in place by the sides of a rectangular hole orslot H in the form sheathing Sh, through which hole the anchor extends,and by a nail 7 driven into the stud through one The nail may be drivenin part way and then bent over, leaving it easy to pull later. Whatappears to be a small extension of part 3.2 of portion 3, which overlapsthe form in the upper part of hole H, has two functions: it helps tokeep the anchor in its proper position in the form, and itl helps toprevent leakage in this part of the said hole. However, since it liesoutside of the surface of the concrete, it really belongs to portion 4of the anchor, rather than to portion 3, and really does not form partof the sector. l

`The, shoulders indicated at 4.2 serve to support the sheathing alongthe greater portion of the vertical edges of the hole or slot H againstthe pressure of the concrete, leaving only a smaller portion at the topof the hole unsupported.

After the anchor 2 has been placed in the form, the link 1 is loopedover the projection 3.1 and a pin 6, which may be a nail, is driventhrough the hole 3.4. The pin 6 extends to the projection 3.1 andoverlies the end of the link 1, thus maintaining the connection betweenthe anchor and the link as long as the pin remains in place. The pin 6needs to t only loosely in the hole 3.4, but the hole is so positionedthat the pin must bend slightly when it is being driven into place, sothat the outer end will spring into the'small depression 4.3 in the topsurface of the portion 4 of the anchor, thus preventing the :pin fromaccidentally working out of place. Instead of having the pin retained bya depression like 4.3 we may, if we want to do so, use any otherirregularity in the top surface of the anchor which will engage theouter end of the pin; thus, a slight projection which would hook behindthe end of the pin would serve the purpose.

It may be noted that the portion of the pin 6 lying Within the hole 3.4is prevented from bonding with the concrete by the surrounding materialof the embedded sector, which makes possible the withdrawal. of the pinAs may be seen in Figures 3 and 4 of the drawing, a small portion of thepin 6, the extreme inner end, is, and must be, exposed to the concrete.However, since the exposed portion is very short, no elective bonding ofthe pin with the concrete, bonding to such `an extent that the bond maynot readily be broken by a moderate pull on the outer end of the pin,can take place. Even an exposed portion of the pin a half inch longwould not effect a prohibitive amount of bonding.

The above-described procedure for placing the anchor vand connecting itwith the link is essentially the same for both sides or" the wall. Thisis also true for the procedure of removing the anchor after the concretehas partly or completely set, which we shall now consider.

The pin 6 may be removed with a pair of pliers, or in case a nail isused, with la claw-hammer or a claw-bar, which will also serve to removethe nail 7. The anchor may then be rotated by tapping the bottom of bar4,1

` be attached to the studs of the forms.

with a hammer. The bottom of bar 4.1 is shown in Figure 4 as beingconvex; this convexity is intended to prevent the lower edges of the twosurfaces which engage the studs from being battered up by hammer blows.The axis of rotation lies at the surface of the concrete opposite thetop edge of the hole H. A point representing this axis is in Figure 4indicated by the numeral 0. The dashed line extending from 0 to 0.1represents a geometrical plane which is normal to the surface of theconcrete and which passes through the axis of rotation. When the anchoris rotated to the extent that the top inner edge of bar 4.1 is broughtinto coincidence with the plane- 0-0.1, the bar has become free fromcontact with the stud. The path of the said edge of'bar 4.1 throughout'the possible rotation is indicated in Figure 4 by the dasheddelineation of a circular arc 5 passing through the points 5.1, 5.2, and5.3. We may note that the clearance between bar 4.1 and' the 4studbecomes progressively greater up to the point 5.2, whence itprogressively decreases. However, by the time point'5.3 is reached, andcontact between bar 4.1 and the stud is re-established, the anchor willhave been completely disconnected from link 1 and may be withdrawn fromthe concrete and from the form.

The initial displacement of the top inner edge of bar 4.1 from the plane0-01 is what makes possible a rotation of suicient extent to effect adisconnection of the anchor from the link, and it makes this possiblewith only a slight effort. We may note that the use of this means forreleasing the engagement of the anchor with the back of a stud, and fordisconnecting the anchor from the link, need not b'e contined to tieswith set-back links v ff In the preceding discussion of the applicationof the present tie, it has been assumed that the anchors would However,it will e seen that the anchors may also readily be attached to wales,horizontal stilening members placed outside of the studs, when this isdesirable. They would be posited so as to make the axis of rotationvertical. Such anchors have to be long enough to extend. back of thewales, -but in other essential'respects these anchors need not bestructurally differentl from those which are applicable to studs.

We may note that after forms constructed with ties of the type herediscussed have beenl stripped from a concrete wall, anchors,particularly stud anchors, may be re-inserted in recesses and applied tovarious. services.

4For instance, a scaffold ledger may be laid on top ot vof variouskinds, members equivalent to the anchors except that the projectingportion is modified to tit each special case, may be inserted inrecesseslocated in suitable positions and used as attachment means forsuch iixtures. In some of such cases the projecting portion may beeliminated entirely andthe xtures secured to the embedded sector by ascrew in a tapped hole or by other means. As long as the inserted memberis prevented from rotating after it has been put in place, it can notcome out unless something breaks, which is not likely, since the stressto be sustained would not in normal cases equal that to which such aconnection would be subjected n a fast high-head concrete pour.

As herein understood, the word frame used in reference to a concreteform means the set of relatively heavy structural members to which thesheathing constituting the face of the form is attached. As herein used,the directions in and out are understood to mean toward the center ofthe concrete in questionY and toward the backside of the form,respectively, unless otherwise indicated.V The Vwords inner and outer inthe claims are to be interpreted in conformity with this. When hereinthe locking pin 6 is mentioned as being maintained in its position by ashoulder in the surface of the anchor, the term shoulder means anyirregularity in said surface of such nature that it can hook behind theouter end of the locking pin, and thereby prevent this from accidentallysliding outward and prematurely disconnecting the anchor from the link;such shoulder or irregularity may be an edge of a notch or depression,or it may be anything equivalent, such as a projection.

I claim:

l. A concrete-form tie comprising a primary member and a pair ofsecondary members, said primary member constituting a set-back linkjoining the said secondary members, each of said secondary membersconstituting an anchor securing the tie to the forms: said anchor havinga portion removably embedded in the concrete, said embedded portionhaving substantially the form of a quadrantal sector of a circle andhaving on its inner extremity a projection engaging the said link; thesaidv anchor beingrotatable, while the form is in place, on an axisformed yby an edge of the set concrete, said axis lying in the planeforming the surface of the concrete; the said anchor having at its outerend a transverse bar engaging the back of the frame of the form, theposition of the engagement before any rotation has taken place beingsuch that all points of the engagement area are displaced from a planenormal to the surface of the concrete and passing through the axis ofrotation of the anchor, the said projection beingof such structure andmagnitude that a rotation of the anchor involving a movement of the saidtransverse bar within a distance equal to twice the originaldisplacement of the said bar will effect a disengagement of the saidprojection from the said link.

2. A concrete-form tie as deiined in claim 1, in which the inner end ofthe said anchor has a hole accessible from the outside of the form, aremovable pin extending through the said hole, said pin engaging thesaid projection and the said link and maintaining the connection betweenthese.

3. A concrete-form tie comprising a primary member and a pair ofsecondary members, said primary member constituting a set-back linkjoining the said secondary members, each of said secondary membersconstituting an anchor securing the tie to the forms: said anchor havinga portion removably embedded in the concrete, said embedded portionhaving substantially the form of a quadrantal sector of a circle, one ofthe two radial sides of the said sector lying substantially parallel toand coincident with the surface of the concrete and the second radialside of said sector lying at substantially a right angle to the surfaceof the concrete, said anchor having a notch extending into it from thesaid second radial side, the inner side of the said notch beingsubstantially parallel to the arc of the said sector, that portion ofthe sector lying between the said notch and the arc of the sectorextending through, and thereby engaging, one end of the said link; thesaid embedded portion of the anchor having a hole accessible from theoutside of the form, a removable pin extending through the said hole andacross the exterior portion of the said notch, thereby maintaining theengagement between the said link and the said anchor.

4. A concrete-form tie as defined in claim 3, in which the non-embeddedportion of the said anchor has a shoulder in its surface, the positionof the said shoulder and the alignment of the said hole being such thatthe outer end of the said pin bears against the said shoulder, the pinbeing thereby maintained in its position.

5. A concrete-form tie as defined in claim 3, in which the portion ofthe said anchor through which the said pin passes, within the said hole,is of sutlicient extent to cover and protect from bonding with theconcrete the major portion of that part of the said pin which lieswithin the surface of the concrete.

6. An anchoring device for attaching xtures to concrete Walls, saiddevice having a primary member consisting of a set-back link permanentlyembedded in the concrete, and a removable secondary member extendinginto the concrete and connecting with the said primary member: theportion of the said secondary member which extends into the concretehaving substantially the form of a quadrantal sector of a circle, one ofthe two radial sides of the said sector lying substantially vparallel tothe surface of the concrete and the second References Cited in the le ofthis patent UNITED STATES PATENTS 871,327 Dietrichs Nov. 19, 1907871,390 Dietrichs Nov. 19, 1907 880,201 Dietrichs Feb. 25, 19081,237,999 Burnett Aug. 21, 1917 1,486,147 Kelley Mar. 11, 1924 1,549,632Trester Aug. 11, 1925 1,981,178 Kavnaugh et al. Nov. 20, 1934 2,750,648

Hallock June 19, 1956

